Extracting ancient DNA samples: “Then, in 2014, another European research team reported that lactase-persistence alleles were completely absent from DNA they had pulled from the bones of Europeans inhabiting the Great Hungarian Plain between 5,700 BC and 800 BC.13 Those ancient DNA analyses suggest that the 13,910*T allele swept across Europe much more recently—probably between 3,000 and 4,000 years ago—than researchers had surmised by studying modern DNA and archaeology.”